Telephone system



Aug 5, 1941 K. SOBOTTA ET AL TELEPHONE SYSTEM Filed Dec. 29, 1939 5 Sheets-Sheet l Inventor KURT SOBOTTA & HANS J. LURK A Home y Aug 1941. K. SOBOTTA ET AL 2,251,301

TELEPHONE SYSTEM Filed Dec. 29, 1959 5 Sheets-Sheet 2 rzsi I VW fiwentor KURT SOBOTTA 8. HANS J. LURK Attorney A g 5, 1- K. SOBOTTA ET AL 2,251,301

' TELEPHONE SYSTEM v I Filed Dec. 29, 1939 5 Sheets-Sheet 5 RI 67115) I 69 m1! E 7' 7E7 I Inventor KURT SOBOTTA 8- HANS J. LURK A ltomey Aug 9 K. SOBOTTA ET AL 2,

TELEPHONE SYSTEM Filed Dec. 29, 1939 5 Sheets-Sheet 4 y l 7402 @3522 7222 69x2 70h2 Inventor KURT SOBOTTA & HANS J.LURK

A ttorney Patented Aug. 5, 1941 TELEPHONE SYSTEM Kurt Sobotta and Hans J. Lurk, Berlin-Siemensst'adt, Germany,.assign0rs to Fides Gesellschaft fur Verwaltung .und' Verwertung von, gewerblichen Sch-utzrechten mit beschrankter Haftung, Berlin, Germany, a corporation of Ger-- many Application-December 29, 1939, Serial No. 311,438

' In Germany November 4, 1938 6 Claims.

The present invention relates: to a; circuit arrangement for telephoneinstall'ationsin: which the calling subscriber at the termination of the conversation ischarged an amount corresponding to the value and duration of the call by means of a time-zone switch operated by metering impulses.

Vlihen connections fromtelephone pay stations are set up the time zone switch takes over the function of determining the correctness of the fee inserted by the subscriber according to the value of the required connection. Metering impulses are transmitted for this purpose; representing; by their number the value of the connection, and are received by aiee -control device operated according to; the inserted amount. If. the fee inserted is correct: the connection is maintained and the amount is collected. If the inserted amount does not. correspond to the selected zone the connection is interrupted and the fee is returned.

In previously known arrangements of, this kind the transmission of the control impulses by the time zone switch occurs at the earliest after the end of the numerical selection. Therefore frequently all the connecting arrangements are heldunnecessaril-yand moreover when a call from the required subscriber is to be prevented un'ti'l availability of, the required amount is testedprecautions must be taken to delay the'ringing of the required subscriber. In order to avoid these disadvantages, according to the invention when the time-zone switch is seized by a telephone pay station the timezone switch is automatically converted for use inan operation which is different from the normal operation occurring when it is seized by a normal telephone station, so as to bring about the transmission of the metering impulses: for supervising the; tee control device directly after the marking digit, actually while the connection is being set up.

Fig. 1 is a lay-out showing in schema-tic form the connections from two; difierent lines.

Figs. 2, 3, 4 and 5, when placed side by side, with 2 at the left and the other sheets placed in order consecutively to the right thereof, disclose the 'etailed circuits for extending connections from any of the subscribers shown in Fig. 1 through the repeater Uel in Fig. 3 over the line VL and repeater Uei! in 4; to the equipmentin Fig. 5 including the zone switch ZZZ.

Fig. 1 shows by means of a circuit diagram somepossib-le' connections in a telephone network;

In the exchange A are includedasubscribers station and pay station Mic. For "the sake of simplicity it is assumed that the stations Tn and Mk in addition to. their preselectors are also provided with separate first group selectors. The stations Tn and Mk can set up connections in the same exchange over first preselectors, first group selectors and final selectors LW. Within the same exchange further subscribers of the exchange A have access over the first group se-' lectors to junction lines VL and hence to the exchange B. The junction line VL is provided at its ends with repeaters Uel and UeZ. In the exchange B over second group selector Z'GW, the third group selector 36W and final selector LW connections can be set up with subscribers of the exchange Bor also over second group selector ZGW junction line VLI third group selector 3GW and final selector LW with subscribers of the exchange C. Finally over the second group selector 2G'W junction line VLI, third group selector BGW, junction line V'LZ, and: final selector LW, connections are possible to the subscribers of the exchange D. The setting up of connections from the exchange A is effected in known manner by selecting various marking digits which are operative on the time: zone switch ZZZ at the incoming end of the junction line. According to the invention the time zone switch operates dif'-' ferently according. to whether it is seized by a subscribers station Tnor a telephone pay station Mic. When it is seized by a subscribers station the discriminator of the time zone switch is positioned, in known manner, by the marking of the zoneafter the reply of the required subscriber. The time switching arrangements in the time zone switch are started in order to determine. the period of the conversation. At the end of the conversation following the hanging up of the receiver by the calling subscriber or automatically after a certain time, for example 12 minutes; the assessor in the time zone switch is operated and brings about the transmission of a number of impulses to the meter of the calling subscriber according to the zone and duration of the conversation.

Ifthe time-zone switch is seized by a telephone pay-station Mk, the discriminator isseized by the first impulse trains; In such a connection a special signal is given after each impulse train, switching over the timezone set so that this set immediately after receipt of the marking digit begins to transmit metering impulses revertively over the junction line without affecting the further impulse trains incoming fromexchange A which serve toposition the remaining selectors. These metering impulse trains are transmitted to the fee control device Gk which is a mechanical device and is arranged within the pay station. These metering impulses are taken up by the fee control device which determines whether the amount inserted corresponds to the selected zone. If this is the case the connection is maintained and the inserted amount is collected, otherwise the connection is interrupted and the inserted amount is returned, the subscriber receiving the engaged signal.

According to a further feature of the invention on the switching over to the time zone switch ZZZ when it is seized by a telephone pay station there is an alteration in the maximum conversation period; a conversation in connections from subscribers stations is limited to 12 minutes and this is automatically cut down in connections from pay stations to 3 minutes.

Finally according to another feature of the invention metering impulses are transmitted in one direction simultaneously with dial impulses in the reverse direction over junction lines by using a differentially connected alternating current relay.

With reference to Figs. 2, 3, 4 and 5 the connection of a subscriber Tn of the exchange A with a subscriber of the exchange B will first be described. Then the setting up of a connection from the pay station Mk of the exchange A also with a subscriber of the exchange B will be described. Only those details necessary for the understanding of the invention are represented and described.

When the subscriber Tn lifts his receiver the preselector VW is started up in known manner. After the setting of the preselector on a further first group selector I GW the test relay To of the preselector VW operates in the following circuit: earth, battery, windings I and II of the relay To, wiper c of the preselector VW, resistance W1 I, contact I Ibg, off-normal contact "5709, earth. The test relay To steps the p-reselector in known manner and guards the seized line against further seizing and switches through the talking conductors to the first group selector. After this switching through, the two battery supply bridge relays Ag and Bg operate over the subscribers loop closed in the first preselector.

Relay Bg by means of its contact I lbg opens the short-circuit for the seizing relay Cg of the first group'selector so that this relay operates over the test conductor, from the preselec'tor. Relay Cg in known manner prepares a circuit for the stepping magnet of the selector. Further relay Cg locks up over contact I5cg independently of off-normal contact Ifikg. By closing of contact log the 'test circuit and the circuit for the transmission of the impulses over the a-conductor are prepared. By means of contact Boy the b-conductor is switched through. At contact I8cg the short-circuit for the winding II of the test relay Pg is interrupted.

When dialling is carried out by subscriber Tn the subscribers loop is intermittently interrupted whereby the impulsing relay Ag alternately restores and operates again. Relay Ag repeats the impulses of the first impulse train to the vertical magnet of the first group selector. The wipers of the group selector are stepped up and perform the rotary hunting operation to seize the free repeater Uel and thus the free junction line VL, Thus the following circuit is completed: earth contacts 10g, Sag, winding I and II of the test relay Pg, wiper c of the first group selector, c-conductor, winding of the relay CI, resistance WiZ, battery, earth. The test relay Pg stops the first group selector and by short circuiting its high resistance winding I at the contact llpg guards the seized junction line against further seizing. At contacts Egg and Illpg the two speaking conductors are switched through to the repeater Uel In the repeater Uel the seizing relay CI operates and closes the following circuit for relay AI: earth, contacts 'I8cI, 82ul, winding of 'the relay AI, battery, earth. Relay AI, by means of its contacts II 3aI and IMaI connects the alternating current source WQ to the junction line VL. This alternating current flows over contact II3aI, regulating resistance Wifi and then from the branching point x in two parallel directions over the windings I and II of an alternating current phase relay II, the windings having separate cores, the repeater winding back to the branching point y, in the opposite direction on the other hand the current flows over the two aditional windings III and IV of the alternating current relay II, the artifical line LN to the branch point y and from there over contact IMaI back to the alternating current source. As indicated in the drawing, the winding III of the relay II is on the same core as the Winding I and the winding IV on the same core as the winding II. The windings III and I as well as windings IV and II of the relay II are clearly of the same dimensions. The condensers connected in series with windings I and II are different in order to follow the phase displacement, but the condenser in series with winding III has the 1 same value as condenser in series with winding I. The same is the case with the condensers in series with windings II and IV. Since the alternating current flows differentially over the two pairs of windings of the alternating current relay when the magnetic field in the relay cores diminishes the relay remains at rest. The relay AI is again restored for a short interval and terminates the seizing impulse. Relay AI on its energisation completes the following circuit for relay VI: earth, windings I and II of the relay VI, contact 'I5aI, resistance WiB, battery, earth. The relay VI operates whereby since the shortcircuit for relays ZI and UI is interrupted at contacts 9IcI, 92cI, these relays are energised in the following circuit: earth, winding of the relay ZI, contact 96H, winding of the relay UI, resistance Wz'4, contact I'MvI, battery, earth. The relays ZI and UI are held energised when relay VI releases and opens contact I041)! over contact I03ul. Relay UI interrupts at contact 82uI the circuit for relay AI. Relay AI restores and hence also relay VI. The seizing impulse is terminated. Relay ZI completes the following circuit for relay GI: earth, contact 992i, resistance Wi5, winding I of the relay GI, battery, earth. After the release of relay VI the relay NI, hitherto short circuited over contacts 6411A and 661 operates in the following circuit: earth, contacts 641, ml, winding II of relay NI, resistance Wzfil, battery, earth. The Win-ding H the relay NI is a high resistance winding so that relay NI does not operate in the circul\t now closed over contact 631d.

In the repeater UeZ at the incoming end of the junction line VL the relay E2 is normally energised over its high resistance winding I in the following circuit: earth, contact 69x2, winding I of the relay E2, contact 'IOchZ and parallel contact I I12, c-conductor, winding of relay C3 in the time zone set ZZZ, contact I36s3, c-conductor of the third group selector, seizing relay in. the third group selector (not shown) battery, earth. The relay C3 in the time Zone set and. the seizing relay in the second group selector are not operated in this circuit. In view of theenergising of relay E2, contacts 26:22 and 21e2; are opened and contact 28e2 is closed. The seizing impulses transmitted from the repeater Uel is therefore taken up by the alternating current relay I2 in the flowing circuit! windings: of the ring repeater, branch point I, in parallel over the windings I and II of the relay I2 as. well as the series condensers, branch point .73, and then, on the one hand, over the regulating resistance Wit, contact 2362, regulating resistance W19, branch point 1/, and on the other hand over the parallel windings' I11 and IV of the relay I2',.the artificial line LN, branch point y, branch point II back to the. ring transformer. The repetition of the incoming current impulses to the speaking conductors is prevented by means of the locking circuit Sp.- Since the alternating current in this case flows in series and in the same sense over the two pairs of windings of the repeating relay I2 the relay.

operates. The following circuit is completed for the relay A2: earth contacts 512, 2g2, 6112, m2; winding of the relay A2, battery, earth. Relay A2 closes the following. circuit for the seizing relay'CZ: earth, contacts llla2, l2ch2, winding of the relay C2, resistance Willi, battery, earth. Relay C2- closes the following circuit for relay CH2: earth, contact 2lc2, winding of the relay Ch2, resistance Will, battery, earth. At the end of the alternating current impulses and the resulting release of relay I2 and A2, the relay C2 is maintained energised in the following circuit: earth, contacts 2lc2, l4f2, l3ch2, winding of" the relay C2, resistance Will], battery, earth. Relay Ch2 connects over contact 83ch2 direct earth to the c condiictor extending to the time. zone switch and thereby seizes the latter. In the time zone set the seizing relay C3 and in the subsequent second group selector theseizing relay, not shown, operates. By the connection of direct earth to the c-conductor the winding I of relay E2 is short-circu'ited. The relay is maintained energised however, in the following circuit: earth,

contacts 2lc2, I'lr2, ltkZ, winding II of the relay E2, battery, earth. After the operation of relays C2 and A2 the following circuit is completed for the relays N2 and V2: earth, contacts 4902, 39:12, winding I of the relay N2, contact llu2, battery, earth. The circuit for the relay V2 is as'follows: earth, contact 4902, 39a2, 55m2,

winding I of the relay V2, battery, earth. Relay V2 completes the following circuit for the relay X2: earth, contact 54122, winding of the relay X2, battery, earth. Relay X2 closes the following circuit for the relay L2: earth, contact 5102, 58:02,

winding of the relay L2, contact 2522, battery, earth. Relay L2 is maintained energised during this operation independently of relay X2 over its contact 5512. Relay X2 is held energised during the operation of relay L2 independently of relay V2 in the following circuit: earth, contacts 49:22, 5 [k2, 5222, winding of the relay X2, battery, earth Relay L2 over contact 2912 connects the relay K2 to the a-conducto'r and over'contact 3W2 the relay R2 to the b-conductc-r.

At the end of the seizing impulses relays I2and A2 restore. The relays N2 and V2 restore one after the other in a delayed manner. Relay N2 is short-circuited over contact 45n2 and its winding II. After relay A2 has deenergised the following circuit for relay U2 is closed: earth, contacts the relay C3 is energised on: seizing. It holds it self energised over contact M603 in. a holding circuit and further completes the following circuit for relay Z3; earth, contacts 9803, I0lv3, wiper dml of the discriminator Dm in its normal position, contact l6li't3, winding I of relay Z3,"

battery, earth.

By the next impulse series the loop of the calling subscriber's station Tn is alternately interrupted and closed. Thereby the impulsing relay Ag of the first group selector oscillates and transm'it's thev impulses in the following circuit to the impulsing relay Al of the outgoing repeater Uel earth, contacts leg, lag, 921,17, wiper a of the first group selector; contacts 61121, 84rd, 83ml, winding .of relay Al, battery, earth. Relay VI is again energised by the first impulse over the contact l5'al, and holds itself energised during the numerical. selection since its winding I is shortcircuited over contact 'lfinl. Over the contacts l'l3al and H4al the alternating current impulses are transmitted over the connecting line VL to the selected repeater. After relay Vl responds, winding II of relay NI is short-circuited over contact 66m. The relay is however held energised in the following circuit: earth, contact 661M, wind-- ing I of relay Nl, contact 63M, winding II of relay M'l, battery, earth. In this circuit relay MI also responds. After the impulse series relays Al, Vl, MI and NI restore, the latter slowly since its winding III is short-circuited over contact In the repeater Uc2 the. impulses from the alternating current relay I2 are received and transmitted to relay A2, over contact 512. Relay A2 transmits the impulses in the following circult. to the impulslng relay A3 of the time zone set: earth, contacts 1222, 140.2, l6u2, 8| g3, winding of relay A3, battery, earth. After the first response of relay A2, the following circuit for relays N2 and'MZ is closed: earth, contacts 4902, 391:2, winding I of the relay N2, winding I of relay M2, battery, earth. Relay M2 breaks the short-circuit over its winding II at contact 43m2 and thereby prepares a holding circuit for itself. Further, relay M2 closes the following circuit independently of relay A2: earth, contacts 4902, MmZ, winding I of relay U2, winding II of relay M2, battery, earth. In this circuitthe relays U2 and M2 are held energised. After the response of relay N2, the following circuit for the relay V2 isclosed: 'earth, contacts 49c2, 5on2, winding I of relay V2, battery, earth. Over contact 461112 the winding II of relay V2 is short-circuited, so that the relay holds itself during the impulse trains. After the impulse trains, relays I2, A2, N2, V2 fall off, the latter slowly.

In the time zone set ZZZ, the setting impulses,

' as already explained, are received by the reseries. R/elay Z3, which has been energized by seizing over wiper dmI in the zero position, holds itself energized until the discriminator has left the zero position during the impulse series in the following circuit: earth, contacts 3803, 99v3, H1023, winding of relay Z3, battery, earth. After the first impulse series has finished relays A3, V3 and Z3 de-energize.

At the second impulse series relay A3 in the time zone set is again impulsively energised, This impulse series is transmitted, to a discriminator MW constructed, for example as a rotary selector in the following circuit: earth, contacts I44t3, H323, II4a3 winding of the rotary magnet MW, battery, earth. At the first impulse relay V3 again responds. The discriminator is switched on step-by-step. When the impulse series ends, relays A3 and V3 restore. Assuming that the discriminator DM is stepped three steps by the first impulse series and the discriminator MW is stepped four steps by the second impulse series, the following circuit for relay T3 is completed at the end of the second impulse series: earth, contacts 9803, H113, wiper dml in position 3, wiper mwIII in position 4, wiper dzIV of the time switch in its normal position, winding I of relay T3, battery, earth. The relay T3 responds and breaks the circuit for the'discriminator MW at contact I4 lt3 so that no further impulses can be received from the discriminator mechanism. Relay T3 holds itself energised in the following circuit: earth, contacts 8903, 9H3, winding II of relay T3, battery, earth. Over contact 81253, relay T3 switches the winding I of relay G3 to the b-conductor.

After receiving the signals of the first two impulse series, the further impulse series are received in the time zone set by relay A3 and like the first two impulse series are transmitted to the final selector by connection of earth to the a-conductor over contact 86113.

When the called subscriber replies potential is applied to the b-conductor in the line selector wherebytherelayG3 in the time zone set responds in the following circuit: earth, battery connected to the b-conductor, contact 8393, winding I of relay G3, contact 8H3, earth. Relay G3 responds and holds itself energised in the following circuit: earth, contacts 3903, 92g3, Winding II of relay G3, resistance WiI2, battery, earth. The winding I of relay G3 is disconnected from the b-condu-ctor at contact 83 3. Relay A3 is disconnected from the a-conductor by contact 8Ig3 and at the same time prepares to connect relay F3 to the a-conductor over contact 89g3. When the called subscriber replies the time switch is disconnected. The following circuit for the rotary magnet Ds of a five-second switch is closed: earth, five-second switch, wiper (1.911 in its normal position, contacts IIIzh3, I I2sm3, H593, winding of the rotary magnet Ds, battery, earth. The selector Ds makes a step after five seconds and goes to position I. From this position it is then switched on by the interrupter Unt to position I in the following circuit: earth, interrupter Unt, wiper dsI, bridged contacts I to '6, contacts I I2sm3, I Ig3, rotary magnet Ds, battery, earth. The selector D3 is set in position I. It is switched on to position 8 over the five-second switch and the wiper dsII. In position 8 in which the selector Ds again remains for five minutes the following circuit for relay Zh3 is closed: earth, contact I45t3, wiper dsIII in position 8, winding of relay Zh3, battery, earth.

After the switch Ds is moved to position 9,

after five seconds of position 8, the following circuit for the minute switch Dz is closed: earth, contact I45t3, wiper dsIII in position 9, contact Il8zh3, rotary magnet Dz, battery, earth. The minute switch goes from position 3 to position I. The switch Ds makes a step further each five seconds driven by the five-second switch over wiper dsII. It travels over the positions I9 to I6, 0, I to 6, I, -8. In between the relay Zh3 restores. In position 8 relay Zh3 is again energised and prepares for further switching of the minute switch. When the second switch ds comes to position 9, the minute switch D2 is again energised over contact II8zh3 and every minute in this manner a step forward is taken.

The time zone switch is provided with an installation for automatic conversation-limiting. If this comes into action the connection is broken after a definite time whereby the selected zone metering impulses are suitably sent to the calling subscriber. If the subscriber hangs up before this time depending upon the time and zone, metering impulses from the time zone set are sent back to the calling subscriber. The switch operations occurring are described in the following. Before that the description of the switch operations are recapitulated, which occur on the response of the called subscriber in the repeaters U62 and UeI.

As already described, on the response of the called subscriber relay F3 is connected to the aconductor over contact 8993. Thereby in the repeater Ue2 the following circuit for the relay K2 connected to the a-conductor is formed: earth, contact I6Iu3, winding I of relay F3, contacts 8993, 'I6u2, 15a2, I3v2, 29Z2, winding of relay KZ, battery, earth. In this circuit the high resistance relay K2 responds but not the relay F3. Relay K2 breaks the holding circuit of winding II of relay E2 at contact H5702, and at contact 5Ilc2, the holding circuit of relay X2. The relays restore. Relay E2 connects the alternating current source WQ to the line VL at its contacts 2662 and 2Ie2. The alternating current traverses the differential system of the two windings of relay I2 so that the relay does not respond. The connection of the alternating current is thereby ended, so that after the response of relay K2 and restoration of relays E2 and X2 the relay L2 is short-circuited over: earth, contacts 64x2, 62e2, 60702; relay L2 again restores and at contact 2912 breaks the circuit'for relay K2. Relay K2 restores, whereby relay E2 again responds over its winding II and the alternating current impulse ends. During the time relay E2 is energised, the following circuit is formed for relay G2: earth, contacts 64x2, 62e2, 6Ik2, winding II of relay G2, battery, earth. After relay E2 responds, relay G2 holds itself energised in the following circuit: earth, contacts 5702, 5992, winding I of relay Z2, winding II of relay G2, battery, earth. In this circuit relay Z2 also responds.

In the repeater UeI the alternating current impulse is received by relay II. Relay II closes the following circuit for relays XI and RI earth, contact IIIz'I, winding of relay XI, winding of relay RI, battery, earth. The relay ZI as this back impulse lasts a comparatively long time is short-circuited over contact 9511, long enough for it to restore. By the opening of contact 992I the circuit for winding I of relay GI is broken so that this relay also restores. After this happens the short circuit for the winding I of relay HI .is opened over contact 9'IgI. Relay HI responds in the following circuit: earth, contact 95H, winding I of relay I-Il, winding of relay Ul, resistance WM, contact lll3ul, battery, earth. Relay I-Il holds itself energised in the following circuit: earth, contacts lltcl, lllshl, winding II of relay HI, battery, earth. Relay Fl is connected to the a-conductor over contact 68hl. After the alternating current impulse concerned comes to an end, relays Il, Rl, Xl restore one after the other. Relay Zl energises again in series with relay test relay Pg is short-circuited. Relay Pg however in spite of that does not restore since the following holding circuit for the winding III of relay-Pg is completed: earth, battery, winding III ofrelay Pg, contacts 30g, 9pc, wiper aof the first group selector, contact tam. winding I of relay F,-eart-h. In this circuit relay Fl responds. Relay Fl completes the following circuit for relay A'l: earth, contacts 8ljl, 83M, winding-of relay Al, battery, earth. Relay Al sends a long-alternating current impulse over the line VL by means of its contacts ll lal and ll3a'l. Therelay Fl closes the following holding circuit for relay Gl: earth, contact l-lillfl; resistance Wit, winding I of relay GI, battery, earth. The alternating current impulse is thereby ended so that the relay Cl restores. This is caused by the seizing relay CI of the repeater Uel being short-circuited over the contacts Blfl and 58ml. Relay Cl restores slowly andshort-circuits the relay Zl over the contacts Mel, Mel, 94ml. Relay Zl restores slowly. After relay Zl has restored, relay Ul is short-circuited over the contacts Blizl and 93ml andlikewise restores. The circuit for the relay Gt is broken after the restoration of relay Z'l at contact 99%! but holds on over contact l'llllfl. After relay U'l restores, the circuit for the relay Al is broken at contact 83ul. Relay III is held energized after relay Cl restores in the following circuit: earth, contacts llififl, lllBgl,

winding II of relay Hl, battery, earth.

In the repeater Ue2 the long release impulse is received by the relay I2. Relay I2 closes the fol lowing circuit for the relay A2: earth, contacts 522, m2, 6n2, I122, winding of relay A2, battery, earth. Relay N2 is again energised over contact -3-9a2: After relay'N2 responds relay V2 *is energised over contact 5Iln2. Relay V2- switches in relay X2 over contact 54112 whose holding circuit wa broken by the response of relay K2 at contact MR2 and after this relay restores at contact 5212. Now relay C2 is short-circuited for an appreciable time over: earth, contacts lliaZ, 2122, relay C2 restores and breaks the circuit for the relays C712 and E2 at contact 2102. The relays however do not restore for after relay C2 restores the relay F2 is energised in thefollowing circuit: earth, contacts 3lc2, 331:2;windihg I of relay F2, contact 2- iz2, battery, earth. The relay F2 holds itself energised further after the restoration of relaysI2, A2, N2, V2 in the following circuit: earth, battery, contact 2522, winding II of relay F2, contacts 3522, 36 2, 13192, l5a2, 'lliuZ, lillg3, winding I of relay F3, {contact lblu3, earth. In this circuit relay F3 of the time zone set also is energised. In

the repeater Ue2 relay F2 holds-on the circuit for the relays E2 and CM at contact I812: earth, contacts lBf-Z, l'lrZ, 16702, winding II of relay E2 and parallel thereto the winding of relay Ch2, resistance Will, battery, earth. Relay Z2 is held energised after the restoration of relay C2 in the following circuit: earth, contact 22ch2, winding II of relay Z2, resistance Wz'l3, contact 2422, battery, earth. The relays N2 and M2 are also held energised over contacts Holt? and m2. Over the contacts 3 222 and 38 2 the winding II of relay R2 is connected to the b-conductor for receiving the metering impulses.

In the time zone set ZZZ, as already explained, the relay F3 is energised as a consequence of the release impulses transmitted from the calling subscriber. Relay F3 closes the following circuit for the assessor switch: earth, interrupter U-nt, wiper do, contact I l9f3, winding of the magnet Da, battery, earth. The selector makes one step and goes from position 8 to position I. From position I the assessor switch is stepped on in the following circuit: earth, interrupter Unt, wiper da, contact l2-6e3, magnet Dc, battery, earth. When the assessor switch reaches the zone selected by the discriminators Dm and Mw and the conversation time arrived at by a suitably marking contact, assuming that the conversation has lasted four minutes, the following circuit for relay E3 is closed: earth, contacts 98c3, WW3, Wiper dml in position 3, wiper mwIII in position 4, wiper d2 IV in position 5, position l l of the assessor switch,

wiper da-I, winding I of relay E3, battery, earth.

The relay E3 responds and holds itself energised in the following holding circuit: earth, contacts 8903, 137 3, l3' ie3, winding II of relay E3, battery,

earth. Parallel to thewinding II of relay E3 windin II of relay Z3 also responds over contacts 1332M, l4lsm3, l39sh3. The assessor switch Da is now no longer connected over the interrupter Unt but is energised step-by-step in the following circuit: earth, contacts F2823, i2le3, rotary magnet Da, battery, earth. Each time the magnet Da is energised the contact i35da3 is closed and the relay Zh3 energised. Relay Zh3 breaks the circuit for relay Z3 at contact l33zh3. Relay 'Zh3 restores. Ihereby'the rotary magnet Da also restores. At contact l35da3 the circuit for relay Zh3 is opened. The relay restores and again closes at contact l33zh3 the circuit for the relay Z3. The assessor switch is thus stepped on simultaneously with the energizing of relays Z3 and 271.3. At each step relay Z3 transmits a metering impulse tothe repeater Ue2 in the following circult: earth, battery, contacts 331*.3, lii'lgmS, 82.23, b-conductor, contact 3372, winding II of relay R2, contact 3422, earth. The relay R2 of the repeater Ue2 responds at each impulse and repeats, as We will show, the metering impulses back to the calling subscriber. If the assessor switch has reached its last position, then after relay Z3 restores the following circuit for the relay SM .is closed: earth, contacts 980-3, l02e3, H1323, ll]'l.cm3,winjding of relay Sh3, last position of the assessor switch, wiper daI, winding I of relay E3, battery, earth. In this circuit relay S1 23 responds, and finally interrupts the circuit for relay Z3 at contact l39sh3. Next the assessor switch ceases to function and the transmission of metering impulses is ended. The holding windingII of relay G3 is .short-circuited over contact 97871.3, so that the relay restores. Relay G3 on restoring opens contact g-3 whereby relay F3 in the timezone set and relay F2 in the repeater Ue2 restore.

When the relay F3 restores the circuit for winding II of relay E3 is broken at contact I3lf3.

In the repeater Ue2 the metering impulses from the relay R2 connected to the b-conductor are .Thereby since relay XI is a slow relay, after relay RI restores, the following metering circuit is formed after each metering impulse connecting to the first group selector: earth, battery, contact 'I IuI, resistance Wilt, contacts 'IZrI, 'IIgI, 'mrl, b-conductor, wiper b of the first group selector, contact Illpg, winding of relay Zg, contact 609, earth. In this circuit the relay Zg of the first group selector responds and transmits over the c-conductor by a current increased by means of the contacts IZzg and 13zg, which short-circuit resistance WiI, the metering impulses to the metering relay Zr in the first preselector. When the metering impulse series comes to an end the continuous alternating current is connected over the connecting line finally energises the relay II. The relays XI and RI are similarly energised for a period. Over contact I!) IrI the winding I of relay GI is short-circuited so that relay GI restores. Further at contact Ififigl the holding circuit for the winding II of relay HI is opened. The relay restores and breaks the circuit for the relay FI in the repeater UeI at contact 63M and for the winding III of relay Pg in the first group selector. I

Relay Pg, which until now has held the connec tion to the first preselector at contact I3pg restores. Thereby the disconnection of the first group selector and the previous preselector occurs in known manner. In the repeater UeI after discontinuation of the blocking alternating current over the connecting line, the relays II, RI, XI restore. Then all the relays of the repeater are again in their rest positions.

Inthe repeater U62 when the metering impulse has been repeated as already explained the relay F2 restores. When relay F2 restores the relays Ch2 and E2 restore since their circuits are broken at contact Iii 2. When relay E2 restores continu ous alternating current is sent back over contacts 2562 and 2'Ie2 and connecting line VL which as already shown causes the beforementioned connecting apparatus to be disconnected. Since relay Ch2 restores the holding circuit for relay Z2 is broken at contact 22071.2 and at contact 4'Ich2 the holding circuit for relays U2 and M2 is opened. After relay U2 restores the holding circuit for relay X2 isopened at contact 53142. Relay E2 again energises after relay X2 restores over contact 69x2, and its high resistance winding I as soon as the c-conductor to the second group selector is again switched through and the selector is released.

The direct earth is disconnected from the cconductor leading to the time zone switch at contact 63071.2. Also seizing relay C3 in the time zone set restores. After relay C3 restores the holding circuit for relay T3 is opened. Besides this at contact 9803 the circuit for relays Sh3 and E3,

winding I, is opened. The relays restore. After relay E3 restores the assessor switch is switched into its rest position in the following circuit: earth, interrupter Unt, wiper da, contact I 26e3, rotary magnet Da, battery, earth. When the assessor switch is again in its rest position the time switch D21 is driven back to its rest position in the following circuit: earth, interrupter Unt, wiper da, contact I2Ilc3, wiper d'z, rotary magnet Dz, battery, earth. After the time switch D2 is set back, over wiper dm of the discriminator Dm in its rest position and, when this has reached its rest position, over wiper etc the time switch Ds is driven back to its rest position. Before this after relay T3 restored the discriminator MW has already connected to a path in its rest position (not shown). Thereby the time zone set is again in its rest position.

If the subscriber Tn has not hung up his receiver after 12 minutes in the time zone set ZZZ after minute switch Dz is set round 13 steps in position I3 the following circuit for relay S3 is closed: earth, winding II of relay F3, wiper dzV in position I3, contact I5Dgm3, winding of relay S3, battery, earth. Relay F3 does not respond in this circuit. Relay S3 breaks the c-conductor leading out at contact I36s3 so that the following selector is released. The calling subscriber receives an engaged signal over line Bes, contact M783, winding II of relay F3, earth. The engaged signal is transmitted back over the winding I of relay F3 connected to the a-conductor to the calling subscriber. The calling subscriber thereupon hangs up his receiver and causes thereby a long alternating current impulse to be sent out from the repeater Uel over connecting line to the repeater U62. As already described the long final impulse is transmitted in the repeater U62 such that in the time zone set is induced transmission of a metering impulse corresponding to the time and zone. The switch operations induced thereby have already been described.

When a connection is set up from a telephone paystation Mic of the exchange A with a subscriber of the exchange B the following switch operations take place: The subscriber using the telephone paystation lifts his receiver, insertsthe amount corresponding to the required connection and beginsdialling. When the receiver is lifted the call relay Ric of the first preselector VW associated with the telephone paystation is energised over the subscriber's loop. The call relay closes the start circuit of the preselector in known manner. The preselector rotates step by step until it finds a free line. As soon as this is the case the test relay Tic of the preselector is energised in the following circuit: earth, battery, windings I and II of relay Tic, wiper c of the preselector, contact 36blc, off-normal contact 35klc, earth. Relay Tic is energised, stops the preselector, locks the seized line over contact 30th by short-circuiting its high resistance winding I and switches through the speech conductors; to the first group selector IGWIc over contacts Z'Itlc and 29tk. After this has been switched through both the battery supply bridge relays Ala and Bk respond over the subscribers loop. The relay Bk breaks the short-circuit of relay Ck at contact 3517K which thereupon responds in series with the test relay Tic of the first preselector. Relay Bk causes the slow relay Vic to energise over-contact 31bit.

During the numerical selection the relay Ak in'the first group selector IGWlc oscillates and ther by transmits the impulses of the first impulse series in known manner to the vertical magnet of. the group selector. After this impulse series is received the group selector hunts in the decade selected by the first impulse series. Assoon as a free line is found the test relay Pk of the first group selector is energised in the following circuit: earth, contact 4802:, windings I and II of the test relay Pic, wiper cm of the first group selector, winding of relay CI, resistance Wi2, battery, earth. In this circuit the seizing relay CI of the repeater UeI operates. The test relay Pk of the first group selector stops the wiper in known manner, blocks the seized line by .short-circuiting its high resistance winding I at contact 49pk and switches through the speech conductors at the contacts 30plc and Ilpk.

Relay CI in the repeater Uel energises the relays AI, VI, 2!, UI, GI, as in a connection originated by the usual subscriber. Relay AI by means of its contacts MI and IMaI transmits 'a short alternating current impulse over the connecting line VL. The alternating current impulse is ended when relay UI is energised. Relay Ul causes relay AI to de-energise. After relay AI is restored relay VI also-restores. Therelays CI, Z-I, Ul, GI are held energised. After relay V'I has restored the short-circuit for winding II of relay NI is broken at contact 661A. The relay N1 is energised over this winding. Howwith the windings II and I of relay NI does not respond on account of the high resistance of the ever, relay MI whose winding II is now in series winding II of relay NI.

In the repeater Ue2 the seizing impulse is received by the relay I2. C712, N2, V2, X2, L2 are energised. The relay L2 connects relay K2 to the a.-'conductor over its contact 2912 and over contact 3012 connects relay R2 to the 'U-cQnductor.

Relay E2 which was held energised before the repeater was seized over its high resistance winding: I by the continuous current is further energised afterse'i-zing the c-conductor leading to the time zone set over its winding II. The time zone set is locked by the direct earthing of the cconductor over contact 630712. After the seizing impulse ends the relays 12, A2, N2, V2 in the repeater U62 restore. The relays C2, Ch2, X2, L2, E2 ar held energised. Apart from this after relay A'irest'ores relay U2 is also energised.

In the time zone set ZZZ the relays C3 and Z3 respond after the seizing operation.

When the second impulse series is sent out by the telephone paystation the relay Ag again oscillates in the first group selector I GWk. The

ir'npulses are transmitted to the repeater Ue-I over the iollowing path: earth, contacts 330k, t'la lc, topic, wiper a "of the group selector IGWIc, contacts 611m, Mal, 831M, winding of relay AI, battery, earth. Relay AI in the repeater UeI transmits the impulses. by means of its contacts II3aI and II laI over connecting line VL. At the first impulse the relays VI and MI in the repeater Ue'I also respond. After the impulse series is finishedrelays AI and VI restore. During the connection prepared by a telephone subscriber after relay V'I restores relay MI immediately restores and relay NI after contact 65ml is closed is held energised further over its high resistance winding. II. Fora connection set up from a telephone paystation relay -MI does not de-energise. Since the short-circuit for winding I'pf this relay :is broken at contact BInI the relay MI is held energised in the following circ'uit: earth,"contaot l'apk, Winding II of relay Pk,

Thereby relays A2, C2,

wiper cmv of the group selector I GWIc, winding I of relay MI, contact 62ml, winding of relay CI, resistance WiZ, battery, earth. Relay NI restores slowly since contact 65ml of the circuit for both of its windings is broken. After relay NI restores the following circuit is again closed to short-circuit relay AI: earth, contacts 8-ImI, 88m, BB' I, winding of relay AI, battery, earth. Relay AI is energised and transmits in addition to the impulse series an alternating current impulse over connecting line VL. This impulse is ended when, after relay NI restores, the winding I of relay MI is also short-circuited over contact 6Inl whereby the relay is restored. After relay MI relay AI also restores. Apart from this relay NI is again energised over its high resistance winding II after relay MI restores.

In the repeater Ue2 the number impulses are received by relay I2 and are transmitted further over the ct-conductor by the relay A2. At the first impulse the relays, N2, M2, V2 are also energised. After the impulse series is finished the relays I2 and A2 restore. After this relay N2 also restores. For a subscribers connection relay V2 also restores but in a connectionoriginiated by a telephone paystation the relay V2 is held energised by the additional impulses trans mitted together with the impulse series which occurs duringthe time this slow relay takes to restore: earth, contacts 522', I102 or parallel contact 292, 6112, 8122, winding of relay D2, winding III of relay M2, winding II of relay V2, battery, earth. In this circuit the relay D2 is also energised. Further the differential winding III of relay M2'is energised in this circuit and therelay restores. Relay M2 is thus in this case not held energised as is the case in a usual connection. After the additional impulse is ended the relay I2 restores together with relays V2 and D2.

In the time zone set ZZZ the impulses received by relay A3duri-ng the impulse series are transmitted over contact 85653 and the (z-conductor on the one hand to the subsequent selectors and on the other hand over contact I 3I at to the rotary magnet Dm of the discriminator. During the impulse series relay V3 is energised in the time zone set. After the'impulse series is ended as a consequence of the additional impulses transmitted in connection with the setting impulse series the relay 'Cm3 is energised in the following circuit: earth, contacts 63712, 611122, 65d2, 651:2, conductor cm, winding I of relay Cm3, winding of relay C3, contact M603, battery, earth. Relay Cm3 holds itself energised in the following holdi-ng circuit: earth, contacts 8903, 9Bcm3, winding of relay Cm3, battery, earth. After relay 01113 is energized the following circuit for the rotary magnet Ds in the time switch is-completed: earth, interrupter Uni, wiper 1181 in zero-position, contacts I29cm3, II 693, winding of rotary magnet Ds, battery, earth. The selector Ds travels to position I and from this position is driven by the interrupter Unt without stopping until it reaches position 8. In this position the switch now is set.

At the next impulse the same switch operations occur in the connecting apparatus as in the case of the previous impulse series. In the'time zone switch the impulse series is received by the 'discriminator Mw When" this marking impulse series comes to an end, the relay T3 responds "in the time zone set over the wipers dmI and mw which have been set as well as over the wiper dz in the rest position. This breaks the circuit for the magnet-Mu) at-contact I l4t3 so that thesubsequent impulse series cannot be transmitted further to the discriminator. Relay T3 holds itself energised over contact 9|t3. Over this contact the'relay Tm3 is further energised: earth, contacts 8903, 9|t3, 93sm3, 9591123, 9501113, winding of the relay Tm3, battery, earth. After relay T3 responds relay 2723, is energisedover the wiper dsIII in position 8. Relay Zh3 prepares at its contact I|8zh3 the circuit for the minute switch D2. The second switch Ds is stepped'in the following circuit from position 8 to position 9: earth, interrupter Unt, wiper (181, in position 8, contacts l3lltm3, ||6g3, winding of the rotary magnet Ds, battery, earth. In position 9 the following circuit for the magnet D2 is closed: earth, contact Mt3, wiper dsIII in position 9, contact l l8zh3, winding of the magnet Dz, battery, earth. The minute switch Dz takes one step and goes from position 0 to position I. After relay Tm responds the following circuit prepared for the assessor is completed: earth, interrupter Unt, wiper da, contacts I24tm3, l25zh3, l2'6e3, winding of the rotary magnet Da, battery, earth. The assessor goes from position ll to position I then causes the interrupter Unt and the wiper da to be stepped on until it has reached the contact indicated by the selected marking number. At this point relay E3 responds overits winding I: earth, contacts 9803, I 01123, wiper dmI (e. g. in position 3), wiper mwIII (e. g. in position 2), wiper 112111 in position I, wiper daI, winding I of the relay E3, battery, earth. Relay E3 holds itself energised in the following circuit: earth, contacts 8e03, I38tm3, l34c3, winding II of the relay E3, battery, earth. Parallel to the winding II of the relay E3 relay Z3 is held energised. Moreover the rotary magnet Da receives impulses over earth, contacts l28z3, l21e3, winding of the rotary magnet Da, battery, earth. At each impulse the relay Zh3 is also energised over contact l35da3 so that the relay Z3 is de-energised at contact I33zh3. The interaction of relay Z3 and Zh3 switches the assessor step by step until it reaches the rest position. Each time relay Z3 is energised an impulse is sent back over the bconductor bya contact 8223 which in the repeater Ue2 is received by the relay R2 in the following circuit: earth, winding I of relay R2, contacts 3622, 37 2, 8223, I6'lg1n3, 83723, battery, earth. During the repeating back of the metering impulses, the impulse series sent out further by the telephone paystation for setting the line selector are transmitted in the following circuit from the repeater Ue2 to the time zone set: earth, contacts 1222, (12, 76142, 8|g3, winding of the relay A3, battery, earth. The impulses received over the a-conductor are transmitted further by the relay A3 by means of contact 85a3 as earth impulses.

In the repeater Ue2 relay R2 breaks the circuit for the Winding II of the relay E2 each time it is energised. Relay E2 repeats the metering impulse by means of its contacts 25e2 and 2'le2 as alternating current impulses backwards over the connecting line. During this transmission back of alternating current impulses, since the alternating current relay I2 is not operated on account of its differential connection, the relay is energised by this simultaneous setting impulse occurring in the opposite direction since these flow through relay windings in series and thereby make the two windings III, IV of therelay operative. Relay I2 responds and the repeating, relay A2 transmits the setting impulses, as already explained-to the impulse receiving relay A3in the time zone set. e r

In the repeater Uel the metering impulses are received by the alternating current relay Il Relay Il responds in thiscircuit. Simultaneously the transmitted setting impulses are conducted over the relay in the opposite direction. The setting impulses transmitted from the group selector .GWk are received in the repeater Uel by the receiving relay A! which is connected to the a-conductor and these impulses are transmitted further by means of its contacts Il3al and [Hal as alternating current impulses. The metering impulses which are received in the repeater Uel via relay II cause relays XI and Rl to be energisedin series. At the end of each impulse the r metering impulses are transmitted back by the aid of both these relays over the a-conductor to the group selector GWk. The relay Zl, temporarily sh-ort-circuited at each metering impulse by contact H does not restore during the short metering impulses.

In the group selector lGWIc the relay Zk: is energised by the metering impulse in the following circuit: earth, Winding of the relay Zk, choke, contact I Epic, wiper b of the group selector lGWlc, contacts 6922!, 1am, 'Hgl, 12ml, resistance W114, contacts I3hl, battery, earth. Relay Zlc connects alternating current of 50 cycles per second to both the speaking conductors in parallel over contact 452k. These alternating current impulses are received by the magnet ZM of the fee control apparatus'GK at the telephone paystation, tuned to this frequency. The circuit for this is as follows: earth, alternating current source, 50 cycles per second, contact 5,270 parallel on the one hand over the a-conductor, a-wiper of the preselector, contact Z'ltk, hook switch contact Hu, choke, condenser,v on the other hand over the b-conductor, b-wiper, of the preselector, contacts 29th, 251m, choke, condenser, winding of the magnet Zm, earth.

The numerical impulses are transmitted on he part of the telephone paystation simultaneously in the opposite direction by intermittent interruption of the subscriber's loop by which the relay Ak is'temporarily restored. At each metering impulse the relay Xlc in the group selector lG-Wlc is also energisedz. earth, contact 40zk, windingof the relay X70, resistance W215, battery, earth. Relay Xk; switches in the slow relay Ylc over contact 383270. During the metering impulse therelay Xk is short-circuited impulsively over the contacts Male and 62:1 :70. It holds itself energised over contact 390%.

The fee control apparatus Gk at the telephone pay-stationis so constructed that the magnet Zm transfers one of the coins inserted in the coin chute, each time metering impulse is received, to an intermediate container. Each time a coin is transferred from the coin chute the contact 22m is opened. On the other hand each time magnet Zm is energised contact 232m is closed. The contacts are so adjusted that contact 232m closes only if contact 22m is already open. If as many coins have been inserted as impulses are received from the magnet ZM the correspondence isso-controlledthat after the relay Zk: in the group selector lGWlc finally is restored, relay Xk: short-circuited for a time long enough to cause it to restore. Relay Xlc breaks the circuit for the slow relay Ykn During the. time relay Ylc is restoring alternating current of cycles per second is temporarily connected to both speech leads in parallelv which, in the fee control apparatus, energises the pay magnet KM tuned to this frequency: earth, alternating current source 100 cycles per second, contact 4150K, 4602K, parallel over both speech leads, magnet KM, earth. As soon as the pay magnet KM has responded the coins are finally transferred to the cash box. I

If the coins inserted in the fee control apparatus do not correspond with the metering impulses occurring, if for example a coin too little is inserted, at the last impulse the contact 23am is closed, but contact 22m is not opened. Thereby relay RM is energised in the following circuit: earth, contacts 232m, 22m, winding of relay RM, choke, hook switch contact Hu, contact Zltk, wiper a of the preselector winding I of the relay Alc, battery, earth. After magnet ZM restores a circuit for the relays RM and A70 is held on over contact 2 lrm. Relay RM breaks the b-conductor at contact 251% and also the connection. In the group selector GWIc the relay Bk restores, Relay Vic also restores at the same time. Also buzzer current is connected to the winding II of relay Ale: line Su, contacts Male, 43bit, winding II of the relay Ak, earth. The buzzer current is inductively transmitted to the winding I of relay Ak. The subscriber receiving engaged signal, replaces his receiver. When the receiver is replaced the money which has been inserted is returned from the intermediate container. The circuit for the relay RM and Ale is broken by the hook switch contact Ha. After relay Bk is restored relay Ck which is short-circuited over contact 362k also restores. Thereby Winding II of relay Pic is short- From the on its part, then causes disconnection to take place in a backward direction. The switch operations are described more particularly later on.

In the time zone set the transmission of the metering impulses is ended so that on the last in the following circuit: earth, contacts 9803, lil2c3, H3323, Hi5gm3, lli lcm3, winding I of relay Sms'i, wiper drlI, winding I of relay E3, battery, earth. Relay Smt breaks the circuit for the relay TmS, at contact 93sm3 so that it restores. contact i lismti the circuit for winding II of relay Z3 is broken. Relay Sm3 holds itself energiscd in the following circuit: earth, contacts 8903, M753, ii lsmt, winding of relay Sm3, battery, earth. Further relay Sm3 closes the following circuit for the rotary magnet of the assessor: earth, interrupter Uni, wiper do, contact l5ilsm3, winding of the rotary magnet Da, battery, earth. The assessor returns to the position ii. The relay the holding circuit of which has already been broken at contact l38tm3 finally restores after the assessor has travelled back to its rest position since the winding I is de-energised.

As soon as the called subscriber answers at the end of the selecting operation relay G3 is energised over its winding I by potential applied to the b-conductor. Relay G3 holds itself energised over its contact 92,173 and the winding II in a holding circuit. Parallel to this, relay is energised: earth, contacts 8902i, 9293, Hlllsm3, winding of relay Gmii, batterv, earth. Relay Gm3 lock-s itself up over its contact [429171 3 in a holding circuit independent of relay .Sm3. After relay Gmt is energised the following circuit .45 step of the assessor the relay Sm3 is energised for the rotary magnet D2 of the minute switch is (closed: earth, interrupter Unt, wiper da. in position I), contact i23tm3, I22gm3, l2lsm3, wiper dz, winding of the rotary magnet Dz, battery, earth. The minute switch is stepped on into its rest position by the interrupter "Uni. As soon as it has reachedthis position the rotary magnet Dm of the discriminator is energised over the rest position of the wiper d2: earth, interrupter Uni, wiper da, contacts seems, lflzgmt, l2lsm3, wiper dz in the rest position, wiper dm winding of the rotary magnet Dm, battery, earth. The

discriminator is stepped on into the rest position.

When it has arrived in this position the second switch D8 is switched into its rest position over the interrupter Uni. Finally the second discriminator MW is brought into its rest position in a manner which is not shown here. As soon as the second switch Ds returns to its zero position the following circuit for the differential winding II of relay Sm?) is closed: earth, contact M553, wiper 628111 in position ii, contact l32sm3, winding II of relay Sm3, battery, earth. The relay S7713 restores. After relay Sm3 is restored the magnet Us is energised again the following circuit: earth, 5 second switch, wiper dsII in position ii, contacts M92713, Htsmt, H593, winding of the rotary magnet 138, battery, earth. The switch steps'from position i to position I. Over the wiper dsI the switch is stepped on in the next 5 seconds by the interrupter Uni over the positions 1-3 to i. In the position i the switch stays again for 5 seconds. Thereupon it is switched on over the wiper dsII to position 8. In position 3 the relay Zh3 is energised over the wiper dsIII. After a further 5 seconds the switch Ds reaches the position 9 in which the minute switch Dz receives the impulse over the wiper 035111 and contact Iliizhti. The minute switch takes one step and travels from position i) to position i. The second switch D5 is now stepped onso that after a minute switch D2 is again energised.- Ihis action is repeated until the calling subscriber hangs up or, automatically at the end of 3 minutes, the disconnection of the connection occurs.

Vfhen the called subscriber answers the following circuit for relay K2 in the repeater U6?! is closed: earth, contact it 5113, winding I of relay F3, contacts Mot, 16142, 550.2, 2932, winding of relayKZ, battery, earth. The relay F3, in the time zone set does not respond in this circuit. Relay K2 in the repeater Uei breaks the circuit for winding II of relay IE2 at contact itkl. Relay Ell restores and transmits a long alternating current impulse back over the connecting line. Each time relay K2 is energised the holding circuit for relay X2 is opened at contact EH02. Relay X2 restores whereby relay L2 is short-circuited over earth, contacts 6M2, 6262, 6M2. Relay L2 restores and thereby disconnects relay K2 from the zit-conductor at contact 2912. At contact 3312 winding I of relay R2 is disconnected from the b-condu'ctor. Relay K2 restores whereupon the relay E2 again responds. During the time the relay E2 is energised the following circuit for relay G2 is closed: earth, contacts fi ixz, 62e2, Mk2, winding II of relay G3 battery, earth. After relay G2 responds it looks itself up in the following circuit: earth, contacts H02, 5992, winding I of relay Z2, winding II of relay G2, battery, earth. In this circuit the relay Z2 is also energised.

In the repeater Uel the long alternating current impulse occurring when the called suhscriber replies, causes relay II to energise. Relay II again energises the relays XI and RI over its contact IIIiI. Over contact 9511 moreover, the relay ZI is short-circuited for a time long enough for it to restore. Relay GI also restores since contact 93zl is opened. After relay GI restores the short-circuit for the winding I of relay HI is opened so that this relay is energised with the relay UI over contact 9511. Relay HI holds itself energised after it responds over its winding II. Relay HI connects relay FI to earth from the a-conductor over its contact Slihl. At the end of the impulse, relays II, RI, XI restore one after the other. Thereupon the relay ZI also 510k, however, does not restore since it is held energised in the following circuit: earth, battery, winding III of relay Pk, contacts 3207c, 301070, wiper a of the group selector IGWlc, contact 68M, winding I of relay Fl, earth. In this circuit the relay Fl of the repeater Uel also responds. The relay Fl short-circuits the seizing relay CI over its contact 51 fl so that this restores. Relay Fl energises the relay Al over contact 8IJI. Relay AI transmits a long disconnecting impulse over the connecting line VL which is ended when relay UI restores. After relay C I restores the relay ZI is short-circuited over contacts 9Icl, 92cl, 94ml, so that this restores. Over contact 90cl,

98ml, the relay UI is short-circuited so that this H relay also restores. After relay Cl has restored the relay HI is already energised in the following circuit: earth, contacts I IIEJI, Illtgl, winding II of relay HI, battery, earth. The relay GI is held energised in the following circuit: earth, contact Illllfl, resistance, wz'5, winding I of relay GI, battery, earth.

In the repeater Ue2 the relays I2, A2, N2, V2, X2 are energised by the long releasing impulse. The relay G2 is short-circuited for a time long enough for it to restore. After relay C2 has restored the relay G2 is also energised in the followingcircuit: earth, contacts 512, 3g2, winding I of relay G2, battery, earth. Relay Z2 is held energised after relay C2 restores in the following circuit: earth, contact 22ch2, winding II of relay Z2, resistance Wil3, contact 2422, battery, earth. Relay C712 is held energised after relay C2 restores over contact I8f2. Relay F2 which is energised in the following circuit after relay C2 restores and relay V2 is energized: earth, contacts 3Ic2, 33122, winding I of relay F2 contact 2422, battery, earth, is held energised after relay V2 restores in the following circuit: earth, battery, contact 2422, winding II of relay F2, contacts 3522, 3612, I302, 15a2, 'I6u2, 83; 3, winding I of relay F3, contact I6lu3, battery, earth.

In the time zone set relay F3 responds in this circuit. Relay F3 energises relay S3 over contact IIOf3. Relay S3 causes the disconnection of the subsequent selector by breaking the c-conductor at contact I36s3. Moreover, the assessor again begins to operate: earth, interrupter Uni, wiper da, contact Il9f3, winding of the rotary magnet D'a, battery, earth. The assessor which after leaving the rest position is stepped on over wiper da. and the contact segment which is switched through is stepped on until it is in the penultimate position in which the relay E3 is energised: earth, contacts 8903, 9lt3, 33.91223, I64gm3, I65f3, wiper daI, winding of relay E3, battery, earth. Relay E3 responds and locks itself up over: earth, contacts 8903, I'I3f3, I3 le3, winding II of relay E3, battery, earth. Parallel to this the relay Z3 is energised. Metering impulses are sent back but not transmitted forward since the circuit is broken at contact I6'Igm3. The assessor moreover is stepped over contacts I2'Ie3 and I23z3 to the last position in which the relay S723 is energised. Here the assessor is next stopped since at the contact I39sh3 the circuit for the relay Z3 is broken. Relay Sh3 short-circuits relay G3 over contact 9'lsh3 so that this restores. The restoration of relayG3 is followed also by the restoration of relay Gm3 and further at contact 8993 the circuit for the relay F3 in the time zone set and relay F2 in the repeater Ue2 is broken. When relay F2 restores the guard on the c-conductor in the repeater Ue2 is lifted so that relay C3 in the time zone set also restores. When relay C3 restores the holding circuit of the relays C7123, T3, S713 and E3 is broken. When relay E3 restores the assessor is returned to its rest position over contact I26e3. When the assessor has reached its rest position the time switches D2 and D5 are returned to their rest positions over contact I2Ilc3.

As soon as the relay F2 connected to the aconductor in the repeater Ue2 restores, the holding circuit of the relays C112 and E2 is opened. Relay E2 conducts alternating current back over the connecting line. After relay Ch2 restores the relays U2, M2, Z2, X2 also restore. Relay Ch2 disconnects the locking potential at contact 63ch2 from the c-conductor leading to the time zone set. This conductor is further interrupted during the time that relay X2 is restoring at contact 69x2 so that the seizing relay C3 in the time zone set restores. The transmission of the alternating current back to the connecting line is again interrupted as soon as relay E2 is energised over its high resistance winding I over the cconductor leading to the time zone set and the subsequent group selector when relay X2 has restored.

In the repeater Uel the relay II, XI, RI are energised one after the other by the alternating current impulses transmitted back over the connecting line. Relay RI short circuits the winding I of relay GI over contact IEII I. Relay GI restores whereby the holding circuit for the relay HI is opened at contact I38gl. Relay HI breaks the circuit for relays FI and Pk at contact 687M. Relay FI restores whereby the repeater Uel is in its rest position.

In the group selector, the test relay Pic restores and causes the disconnection of the group selector and the previous preselector,

If the calling subscriber at the telephone pay station does not hang up his receiver in three minutes, after this time an automatic disconnection of the line ensues in the time zone set so that in position 4 of the minute switch Dz the following circuit for the relays S3 is completed: earth, winding II of relay F3, wiper (1.2V in position 4, wiper dmII in position 0, contact IGBgmS, winding of relay S3, battery, earth.

Relay S3 breaks the outgoing c-conductor and initiates the disconnection of the subsequent selector. The calling subscriber receives the engaged signal over contact M183 and the winding 11 of relay F3 and which is inductively transmitted to the winding I of relay F3.

If the calling subscriber thereupon hangs up his receiver the same switch operations take place as have been described above. A longer disconnecting impulse is transmitted from the repeater Uel to the repeater U62 so that the time zone set is restored to the rest position and simultaneously the connection is released revertively.

We claim:

1. In a telephone system, wherein calls are extended from paystation telephones and regular telephones in one exchange to called lines in other exchanges, a time zone switch in one exchange operated in accordance with the value of a connection to transmit impulses back to the calling subscriber varying in number in accordance with the connection extended to assess a charge for the connection, means for causing said switch to function in one manner when called from a regular telephone and in a difierent manner to transmit impulses to the calling telephone while the connection is being extended to automatically control the collection of a plurality of coins thcreat when called from a paystation telephone.

2. In a telephone system, means for extending connections from two different types of telephone lines to lines in other exchanges, a toll assessing device accessible to both lines, said device operable during the extension of a connection from one type of line to transmit a number of impulses back to the calling telephone line after the connection is completed varying in number in accordance with the value of the connection, said assessing device operable during the extension of a connection from the other type of telephone line to transmit a particular number of impulses back to the calling telephone line during the extension of the connection varying in accordance with the value of the connection.

3. A telephone system as claimed in claim 2 wherein the impulses transmitted back to the calling telephone line can be transmitted at the same time the impulses for extending the connection are being transmitted in the other direction.

4. A telephone system as claimed in claim 1 wherein there are provisions for transmitting alternating current impulses in both directions over the connection simultaneously.

5. In a telephone system, automatic switches, means for operating said switches for extending connections of different value and for controlling the operation of said switches by transmitting alternating current impulses in one direction over the connections, an assessing device in each connection for returning impulses of alternating current thereover to automatically assess toll for the connection, an alternating current relay in each connection connected as a differential relay, the said alternating current impulses passing through said relay in both directions simultaneously over the connection without interference. v

6. In a telephone system, means for extending toll connections from regular or paystation lines, an assessing switch included in all connections and variably operated during the extension of a connection, in accordance with the value thereof, to transmit a number of impulses to automatically assess charges therefor, means for transmitting the impulses for setting the connection over one conductor and the assessing impulses over the other conductor when a regular line extends a call, and means for transmitting the impulses for setting a connection extended from a paystation simultaneously with the transmission of the assessing impulses transmitted in the opposite direction.

KURT SOBOT'I'A. HANS J. LURK. 

